The invention relates to methods for fabricating insulating glass assemblies, and more particularly to methods for filling the spaces between the panes of glass assemblies with gas.
A conventional insulating glass assembly includes a pair of generally parallel, spaced glass panes defining therebetween a space and having therebetween an endless spacer. A typical spacer is made of extruded metal, is rectangular in cross section and has a hollow interior. The inner wall of the spacer has therein a plurality of holes or perforations, and the spacer has within its interior a desiccant that absorbs moisture from the gas within the space between the panes. The spacer is bonded to the panes by a suitable material such as polyisobutylene.
Various methods are known for replacing air in the space between the panes with a gas having a coefficient of thermal conductivity lower than that of air. U.S. Pat. No. 4,780,164 discloses a method in which a plurality of insulating glass assemblies are arranged with their panes extending in parallel, vertical planes and are placed within a vacuum chamber. Each of the glass assemblies has an opening in its spacer. The chamber is evacuated, so that the spaces between the panes of the glass assemblies are evacuated, and the chamber is then filled with a gas having a coefficient of thermal conductivity lower than that of air, so that the spaces between the panes of the glass assemblies are filled with gas. Finally, the assemblies are removed from the chamber and the openings in the spacers are sealed.
It is commonly believed that it is necessary to have the glass assemblies oriented vertically within the vacuum chamber and to have the openings located in the tops of the glass assemblies so that the gas does not leak out of the glass assemblies before the openings in the spacers are sealed.